In modern radio receivers, some form of automatic gain control (AGC) for a receiver is typically used. Such AGC can be used to counter component variation, which may translate into gain variation as a function of varying process parameters. This gain variation is undesirable in most modern radio receivers because a received analog signal may be transformed into a digital signal, which can be corrupted as a result of the gain variation.
FIG. 1 shows a conventional AGC loop 100 in a receiver. An input signal (e.g., from an antenna) can be received in low noise amplifier (LNA) with gain control 102. Mixer 104 can receive an output from amplifier 102, as well as a reference clock 106. AGC logic 108 can monitor the mixer output, and provide adjustment controls to amplifier 102. However, such conventional approaches may not provide AGC lock detection. Thus, an AGC approach suitable for controlling an amplifier and producing a signal indicating that the AGC is near or in its optimal (or locked) state would be advantageous.